TUESDAY, Dec. 19, 2017 -- Luxturna, a form of gene therapy, has been approved to treat a rare group of inherited vision disorders that can lead to blindness.

The disorders are broadly grouped together and known as biallelic RPE65 mutation-associated retinal dystrophy. They affect a combined 1,000 to 2,000 people in the United States, the U.S. Food and Drug Administration said Tuesday in a news release.

Luxturna (voretigene neparvovec-rzyl) delivers a working copy of an existing defective gene that produces a retinal enzyme needed for normal vision.

"Today's approval marks another first in the field of gene therapy, both in how the therapy works and in expanding the use of gene therapy beyond the treatment of cancer to the treatment of vision loss," said FDA Commissioner Dr. Scott Gottlieb. "I believe gene therapy will become a mainstay for treating, and maybe curing, many of our most devastating and intractable illnesses."

Luxturna should be given only to people who have treatment-capable retinal cells, the agency said. Treatment must be done separately on each eye, at least six days apart.

The treatment was evaluated in clinical trials involving 41 people ranging in age from 4 to 44. The most common side effects included eye redness, cataracts, increased eye pressure and retinal tear.